With recent development of relatively high-speed wireless communications networks, wireless connectivity has become one of the fastest growing methods for implementing communications networks. Wireless networks provide fast deployment due to their elimination of the need to create a wired network infrastructure and freedom of movement since the wireless communications devices are not tied down to a specific location by the network cable. The inherently more expensive equipment (transmitters and receivers) is often more than offset by the rapid deployment and freedom of movement that they provide.
However, the freedom of movement in wireless communications devices is limited by the transmitters (and the transmit power) at both the wireless communications device and the wireless network infrastructure. The amount of transmit power is regulated by the government to minimize the impact of these wireless communications networks on other electronic devices and networks. The transmit power is further constrained by heat dissipation and battery life concerns. Additionally, physical constraints such as maximum propagation delay and latency also place a limit on how far a wireless communications device can travel from its wireless network before the wireless network stops working.
One way to increase the effective operating range of a wireless communications network is to have multiple transmitters and receivers with enhanced capabilities (transceivers) in the wireless network infrastructure. These transceivers have enhanced capabilities to allow them to control the communications and operations of the wireless communications devices. In some wireless networks, these transceivers are often called wireless access points. With multiple wireless access points, a wireless communications device can switch from one wireless access point to another whenever the wireless communications device moves outside of a coverage area covered by one wireless access point into a coverage area provided by a different wireless access point. The process of moving from the control of one wireless access point to another is known as roaming, with the exchange between one wireless access point to another being known as a handoff.
Roaming permits the enlargement of the coverage area of a wireless communications network through the use of multiple wireless access points without needing to increase the transmit power of the wireless devices and while remaining under the restraints set forth by governmental regulations and the laws of physics.
In wireless communications networks adherent to the Institute of Electrical and Electronics Engineers 802.11 Wireless Local Area Network technical standard (commonly referred to as IEEE 802.11 WLAN networks), when a wireless communications device leaves the coverage area of a first wireless access point, it stops communications with the first wireless access point and attempts to initiate communications with a second wireless access point. This process is known as disassociating and reassociating, wherein the wireless communications device disassociates with the first wireless access point and reassociates with the second wireless access point. Unfortunately, the disassociating and reassociating process can take an extended amount of time, especially with the need to re-authenticate the wireless communications device with the second wireless access point. Re-authentication is needed because a wireless communications device cannot simply be added to the network, since doing so could compromise the security of the network. During this extended period of time, the wireless communications device cannot communicate with any device other than the second wireless access point. Additionally, should the reassociating fail, the wireless communications device may not be able to communicate for an extended amount of time while it attempts to establish a communications link with a different wireless access point.
A need has therefore arisen for a faster and more efficient roaming handoff procedure that does not require that the wireless communications device disconnecting with one wireless access point until it is sure that it can reconnected with another.